ADO.NET Data Services

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ADO.NET Data Services

• Mike Taulty
• Developer Platform Group
• Microsoft UK
• Mike.Taulty_at_microsoft.com
• http//www.miketaulty.com

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Agenda

• Overview of ADO.NET Data Services
• Exposing Data Sources
• Custom data sources, LINQ to SQL, LINQ to
  Entities
• Building Clients
• .NET Clients, AJAX based clients
• More advanced topics
• Interception
• Service Operations
• Batching of operations
• Dealing with concurrency

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Data Services Overview

• Builds on top of WCF V3.5
• Provides new functionality
• CRUD access to data over RESTful web services
• Built-in URI-based query syntax
• Client-side libraries for .NET, AJAX and
  Silverlight
• Status
• In VS 2008 Service Pack 1, Ships Summer 2008
• Current version is in Sp1 Beta 1 but has been
  through various previews

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RESTful Web Services?
HTTP Request
URL
VERB
Payload
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RESTful?

• REpresentational State Transfer
• Server-side resources identified by a URI
• Access is over HTTP, verb tied to action
• GET to read the value of a resource
• POST to create a new resource
• PUT to update an existing resource
• DELETE to delete a resource
• Returned data is plain XML or JSON
• Is this the death of SOAP?

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Data? What Kind of Data?

• Provide a type with public properties which are
  IQueryableltTgt
• Some rules about how T has to be formed
• Remember the extension method AsQueryable()
• Only get write access if your type implements
  IUpdatable
• Works well with generated code from
• ADO.NET Entity Framework (ObjectContext)
• LINQ to SQL (DataContext)

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DEMO

• Exposing Data with ADO.NET Data Services

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ADO.NET Entity Framework????
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DEMO

• Exposing EF Data with ADO.NET Data Services

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Querying with ADO.NET Data Services

• URI based query mechanism
• http//myservice.svc/MyEntitySet
• Supports the notion of navigating by primary key
• MyEntitySet ( MyPrimaryKeyCol1, Col2, ... )
• Supports various operators
• orderby, top, skip, expand, filter, value

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Operators for filter
Logic
eq
ne
gt
gteq
lt
lteq
and
or
not
Arithmetic
add
sub
mul
div
mod
round
floor
ceiling
String
contains
endswith
startswith
length
indexof
insert
remove x 2
replace
substring
tolower
toupper
trim
concat
Date/Time
second
hour
minute
day
month
year
Type
isof
cast
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DEMO

• Querying Data with the URI

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Building Clients

• Services offer metadata
• MyService.svc/metadata
• .NET clients made easier through a proxy
  generation tool
• datasvcutil.exe
• AJAX clients made easier through a script library
• Data Service AJAX Client Library
• Available as a download on Codeplex

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DEMO

• Building .NET and AJAX clients

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Interception Operations

• Possible to hook code into the dispatch mechanism
• For queries we can write
• Query interceptors
• For modifications we can write
• Change interceptors
• Can also expose custom functionality
• Service Operations
• Useful for providing canned functionality, can
  be parameterised

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DEMO

• Interception and Service Operations

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Batching of Operations
INSERT
Customer 1
Order 1
Order 2
Order N
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Batching of Operations
INSERT
Customer 1
Order 1
Order 2
Order N
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Batching of Operations

• Provides a mechanism to process a batch
• 0 or more Query operations
• 0 or more Create/Update/Delete operations
• Uses multipart/mixed MIME type sent to a batch
  endpoint
• Use
• SaveChanges(SaveChangesOptions.Batch)
• ExecuteBatch()

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DEMO

• Batching of Operations

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Managing Concurrency
Customer ALFKI Country Spain
Customer ALFKI Country Spain
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Managing Concurrency
Customer ALFKI Country Germany
Customer ALFKI Country UK
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Managing Concurrency

• Optimistic concurrency
• Attribute used to specify properties
• Not necessary for Entity Framework data
• Standard HTTP protocol used
• eTags used to send to client ( in XML if
  necessary )
• HTTP If-match headers used to check when
  PUT/DELETE occurs ( 412 returned for failure )

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DEMO

• Managing Concurrency

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Resources

• New Data Developer Site
• http//www.datadeveloper.net
• Data Services (Astoria) Team Blog
• http//blogs.msdn.com/astoriateam
• My website ?
• http//www.miketaulty.com ( search Data Services )

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ado.net data services

• Mike Taulty
• Developer Platform Group
• Microsoft UK
• Mike.Taulty_at_microsoft.com
• http//www.miketaulty.com

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